Fuel cell systems include a fuel cell stack that produces electrical energy based on a reaction between a hydrogen-based feed gas (e.g., pure hydrogen or a hydrogen reformate) and an oxidant feed gas (e.g., pure oxygen or oxygen-containing air). In proton exchange membrane (PEM) type fuel cells, the hydrogen-based feed gas is supplied to an anode of the fuel cell and an oxidant is supplied to a cathode of the fuel cell. PEM fuel cells include a membrane electrode assembly (MEA) comprising a thin, proton transmissive, non-electrically conductive, solid polymer membrane-electrolyte having the anode on one of its faces and the cathode on the opposite face. The MEA is sandwiched between a pair of electrically conductive elements which serve as current collectors for the anode and cathode and contain appropriate channels and/or openings therein for distribution of the fuel cell's gaseous reactants over the surfaces of the respective anode and cathode catalysts. A plurality of individual fuel cells are commonly stacked together to form a PEM fuel cell stack.
Generally multiple fuel cell stacks are arranged in series and are connected via high voltage external connection wires, as illustrated in FIG. 3. The use of external connection wires increases the volume, weight and complexity of the fuel cell stack system. In particular, fuel cell stacks typically have a positive pole 102 and a negative pole 104 that are disposed at opposite ends of the fuel cell stack 100. Thus, in order to connect multiple fuel cell stacks 100, 100a in series, the external high voltage wires 106 are required to run from one end of a fuel cell stack 100 to another end of an adjacent fuel cell stack 100a as illustrated in FIG. 3. The external wires 106 are not protected by contactors, and contribute to increased electromagnetic interference (EMI) that requires shielding or other protection. The external wires 106 also contribute to additional sealing requirements. Thus, fully insulated and shielded wires require a large volume and increase the weight of the fuel cell system. Accordingly, a need exists for a system with reduced external wiring.